1 Features
1• Multiple Frequency Options Available
– See Device Information Table
– Frequencies From: 553 MHz to 3132 MHz
• PLL Features
– Fractional-N Delta-Sigma Modulator Order
Programmable up to Fourth Order
– FastLock/Cycle Slip Reduction with Timeout
Counter
– Partially Integrated, Adjustable Loop Filter
– Very Low Phase Noise and Spurs
• VCO Features
– Integrated Tank Inductor
– Low Phase Noise
• Other Features
– 2.8-V to 3.2-V Operation
– Low Operating Current
– Low Power-Down Current
– 1.8-V MICROWIRE Support
– 36-Pin 6-mm × 6-mm × 0.8-mm WQFN
Package

2 Applications
• Cellular Base Stations
• Wireless LANs
• Broadband Wireless Access
• Satellite Communications
• Wireless Radios
• Automotive
• CATV Equipment
• Instrumentation and Test Equipment
• RFID Readers
• Data Converter Clocking

3 Description
The LMX2531 is a low-power, high-performance
frequency synthesizer system which includes a fully integrated delta-sigma PLL and VCO with fully
integrated tank circuit. The third and fourth poles are
also integrated and adjustable. Ultra-low noise and
high-precision LDOs are integrated for the PLL and
VCO, which yield higher supply-noise immunity and more consistent performance. When combined with a
high-quality reference oscillator, the LMX2531 device
generates very stable, low-noise local-oscillator
signals for up and down conversion in wireless
communication devices. The LMX2531 device is a monolithic integrated circuit, fabricated in an
advanced BiCMOS process. Several different
versions of this product accommodate different
frequency bands.